U.S. patent number 7,615,486 [Application Number 11/736,522] was granted by the patent office on 2009-11-10 for apparatus and method for integrated surface treatment and deposition for copper interconnect.
This patent grant is currently assigned to Lam Research Corporation. Invention is credited to John M. Boyd, Yezdi Dordi, Mikhail Korolik, Fritz C. Redeker, Hyungsuk Alexander Yoon.
United States Patent |
7,615,486 |
Yoon , et al. |
November 10, 2009 |
Apparatus and method for integrated surface treatment and
deposition for copper interconnect
Abstract
A method and system for depositing films on a substrate for
copper interconnect in an integrated system are provided to enable
controlled-ambient transitions within an integrated system to limit
exposure of the substrate to uncontrolled ambient conditions. The
method includes moving the substrate into a processing chamber
having a plurality of proximity heads. Within the processing
chamber, barrier layer deposition is performed over a surface of
the substrate using one of the plurality of proximity heads
functioning to perform barrier layer ALD. In addition, the method
includes moving the substrate from the processing chamber, through
a transfer module of the integrated systems, into a processing
module for performing copper seed layer deposition. Within the
processing module for performing copper seed layer deposition,
copper seed layer deposition is performed over the surface of the
substrate. The processing chamber for performing the barrier layer
ALD and the processing module for performing the copper seed layer
deposition are parts of the integrated system.
Inventors: |
Yoon; Hyungsuk Alexander (San
Jose, CA), Korolik; Mikhail (San Jose, CA), Redeker;
Fritz C. (Fremont, CA), Boyd; John M. (Woodlawn,
CA), Dordi; Yezdi (Palo Alto, CA) |
Assignee: |
Lam Research Corporation
(Fremont, CA)
|
Family
ID: |
39872470 |
Appl.
No.: |
11/736,522 |
Filed: |
April 17, 2007 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20080260940 A1 |
Oct 23, 2008 |
|
Current U.S.
Class: |
438/640;
257/E21.575; 257/E21.577; 257/E21.585; 438/618; 438/637;
438/672 |
Current CPC
Class: |
C23C
16/45544 (20130101); C23C 16/54 (20130101); H01L
21/28562 (20130101); H01L 21/76814 (20130101); H01L
21/76873 (20130101); H01L 21/76843 (20130101); H01L
21/76861 (20130101); H01L 21/76862 (20130101); H01L
21/76826 (20130101) |
Current International
Class: |
H01L
21/4763 (20060101) |
Field of
Search: |
;438/645 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mulpuri; Savitri
Assistant Examiner: Lee; Cheung
Attorney, Agent or Firm: Martine Penilla & Gencarella,
LLP.
Claims
What is claimed is:
1. A method of depositing films on a substrate for copper
interconnect in an integrated system, comprising: moving the
substrate into a processing chamber having a plurality of proximity
heads, selected ones of the proximity heads being configured to
perform at least one of surface treatments and atomic layer
depositions (ALDs), the processing chamber being part of the
integrated system, and within the processing chamber, performing,
barrier layer deposition over a surface of the substrate using one
of the plurality of proximity heads functioning to perform barrier
layer ALD; and moving the substrate from the processing chamber,
through a transfer module of the integrated systems, into a
processing module for performing copper seed layer deposition, the
processing module for performing copper seed layer deposition being
part of the integrated system, wherein the processing module for
performing copper seed layer deposition is integrated with a
rinse/dryer to enable dry-in/dry-out process capability limiting
the exposure of the substrate to oxygen, and within the processing
module for performing copper seed layer deposition, performing,
copper seed layer deposition over the surface of the substrate,
wherein the integrated system enables controlled-ambient
transitions within the integrated system to limit exposure of the
substrate to uncontrolled ambient conditions outside of the
integrated system.
2. The method of claim 1, further comprising: moving the substrate
from the processing module for performing copper seed layer
deposition, through the transfer module of the integrated system,
into a processing module for performing copper gap-fill layer
deposition, the processing module for performing copper gap-fill
layer deposition being part of the integrated, system, and within
the processing module for performing copper gap-fill layer
deposition, performing, copper gap-fill layer deposition over the
copper seed layer of the substrate; and moving the substrate from
the processing module for performing copper gap-fill layer
deposition, through the transfer module of the integrated system
and into a processing module for performing substrate cleaning, the
processing module for performing substrate cleaning being part of
the integrated system, and within the processing module for
substrate cleaning, performing, cleaning of the substrate after the
copper gap-fill layer deposition has been performed.
3. The method of claim 2, wherein the processing module for
performing copper gap-fill layer deposition is an electrochemical
plating (ECP) module.
4. The method of claim 1, further comprising: performing surface
pre-treatment over the surface of the substrate using one of the
plurality of proximity heads functioning to perform surface
pre-treatment in the processing chamber before the barrier layer
deposition.
5. The method of claim 4, wherein the surface pre-treatment is
performed over the surface of the substrate to remove contaminants
or to activate the surface of the substrate for the barrier layer
deposition.
6. The method of claim 4, further comprising: performing liner
layer deposition over the barrier layer of the substrate using one
of the plurality of proximity heads functioning to perform liner
layer ALD in the processing chamber, and performing surface
post-treatment over the surface of the substrate using one of the
plurality of proximity heads functioning to perform surface
post-treatment in the processing chamber after the liner layer
deposition.
7. The method of claim 6, wherein the surface post-treatment is
performed over the surface of the substrate to remove contaminants
or to activate the surface of the substrate in preparation for the
copper seed layer deposition.
8. The method of claim 6, wherein substrate processing on substrate
is performed in the sequence of surface pre-treatment, barrier
layer deposition, liner layer deposition, and surface
post-treatment.
9. The method of claim 6, the metals in the barrier layer and the
liner layer are selected from the group consisting of tantalum
(Ta), titanium (Ti), tungsten (W), zirconium (Zr), hafnium (HD,
molybdenum (Mo), niobium (Nb), vanadium (V), ruthenium (Ru) and
chromium (Cr).
10. The method of claim 1, wherein the processing module for
performing copper seed layer deposition is an electroless
deposition (ELD) module.
11. The method of claim 1, wherein the transfer module and the
processing module for performing copper seed layer deposition are
filled with an inert gas to limit the exposure of the substrate to
oxygen.
12. The method of claim 1, wherein the films deposited on the
substrate for copper interconnect in the integrated system with
limited exposure to uncontrolled ambient conditions outside the
integrated system improve electro-migration (EM) performance for
copper interconnect.
13. The method of claim 1, wherein the barrier layer deposited is
conformal and reduces void formation in copper interconnect.
14. A method of depositing films on a substrate for copper
interconnect in an integrated system, comprising: moving the
substrate into a processing chamber having a plurality of proximity
heads, selected ones of the proximity heads being configured to
perform at least one of surface treatments and atomic layer
depositions (ALDs), the processing chamber being part of the
integrated system, and within the processing chamber, performing,
surface pre-treatment over a surface of the substrate using one of
the plurality of proximity heads functioning to perform surface
pre-treatment in the processing chamber before a barrier layer
deposition, wherein the surface pre-treatment is performed over the
surface of the substrate to remove contaminants or to activate the
surface of the substrate for the barrier layer deposition, and
barrier layer deposition over the surface of the substrate using
one of the plurality of proximity beads functioning to perform
barrier layer ALD after surface pre-treatment; and moving the
substrate from the processing chamber, through a transfer module of
the integrated system, into a processing module for performing
copper seed layer deposition, the processing module for performing
copper seed layer deposition being part of the integrated system,
wherein the processing module for performing copper seed layer
deposition is integrated with a rinse/dryer to enable
dry-in/dry-out process capability limiting the exposure of the
substrate to oxygen, and within the processing module for
performing copper seed layer deposition, performing, copper seed
layer deposition over the surface of the substrate, wherein the
integrated system enables controlled-ambient transitions within the
integrated system to limit exposure of the substrate to
uncontrolled ambient conditions outside of the integrated
system.
15. The method of claim 14, further comprising: moving the
substrate from the processing module for performing copper seed
layer deposition, through the transfer module of the integrated
system and into a processing module for performing copper gap-fill
layer deposition, the processing module for performing copper
gap-fill layer deposition being part of the integrated system, and
within the processing module for performing copper gap-fill layer
deposition, performing, copper gap-fill layer deposition over the
copper seed layer of the substrate; and moving the substrate from
the processing module for performing copper gap-fill layer
deposition, through the transfer module of the integrated system,
into a processing module for performing substrate cleaning, the
processing module for performing substrate cleaning being part of
the integrated system, and within the processing module for
substrate cleaning, performing, cleaning of the substrate after the
copper gap-fill layer deposition has been performed.
16. The method of claim 14, further comprising: performing liner
layer deposition over the barrier layer of the substrate using one
of the plurality of proximity heads functioning to perform liner
layer ALD in the processing chamber, and performing surface
post-treatment over the surface of the substrate using one of the
plurality of proximity heads functioning to perform surface
post-treatment in the processing chamber after the liner layer
deposition, wherein the surface post-treatment is performed over
the surface of the substrate to remove contaminants or to activate
the surface of the substrate in preparation for the copper seed
layer deposition.
17. The method of claim 16, wherein substrate processing on
substrate is performed in the sequence of surface pre-treatment,
barrier layer deposition, liner layer deposition, and surface
post-treatment.
18. The method of claim 14, wherein the transfer module and the
processing module for performing copper seed layer deposition are
filled with an inert gas to limit the exposure of the substrate to
oxygen.
19. A method of depositing films on a substrate for copper
interconnect in an integrated system, comprising: moving the
substrate into a processing chamber having a plurality of proximity
heads, selected ones of the proximity heads being configured to
perform at least one of surface treatments and atomic layer
depositions (ALDs), the processing chamber being part of the
integrated system, and within the processing chamber, performing,
barrier layer deposition over a surface of the substrate using one
of the plurality of proximity heads functioning to perform barrier
layer ALD, surface pre-treatment over the surface of the substrate
using one of the plurality of proximity heads functioning to
perform surface pre-treatment in the processing chamber before the
barrier layer deposition, liner layer deposition over the barrier
layer of the substrate using one of the plurality of proximity
heads functioning to perform liner layer ALD in the processing
chamber, and surface post-treatment over the surface of the
substrate using one of the plurality of proximity heads functioning
to perform surface post-treatment in the processing chamber after
the liner layer deposition; and moving the substrate from the
processing chamber, through a transfer module of the integrated
system, into a processing module for performing copper seed layer
deposition, the processing module for performing copper seed layer
deposition being part of the integrated system, and within the
processing module for performing copper seed layer deposition,
performing, copper seed layer deposition over the surface of the
substrate, wherein the integrated system enables controlled-ambient
transitions within the integrated system to limit exposure of the
substrate to uncontrolled ambient conditions outside of the
integrated system.
20. The method of claim 19, wherein the surface post-treatment is
performed over the surface of the substrate to remove contaminants
or to activate the surface of the substrate in preparation for the
copper seed layer deposition.
21. The method of claim 19, wherein substrate processing on
substrate is performed in the sequence of surface pre-treatment,
barrier layer deposition, liner layer deposition, and surface
post-treatment.
22. The method of claim 19, the metals in the barrier layer and the
liner layer are selected from the group consisting of tantalum
(Ta), titanium (Ti), tungsten (W), zirconium (Zr), hafnium (Hf),
molybdenum (Mo), niobium (Nb), vanadium (V), ruthenium (Ru) and
chromium (Cr).
Description
CLAIM OF PRIORITY
This application claims priority under 35 U.S.C. .sctn. 120 of U.S.
application Ser. No. 11/514,038, entitled "Processes and Systems
for Engineering a Barrier Surface for Copper Deposition" filed on
Aug. 30, 2006, which is herein incorporated by reference.
CROSS REFERENCE TO RELATED APPLICATION
This application is related to U.S. patent application Ser. No.
11/736,514, entitled "Apparatus and Method for Pre and Post
Treatment of Atomic Layer Deposition," U.S. patent application Ser.
No. 11/736,511, entitled "Apparatus and Method for Atomic Layer
Deposition," and U.S. patent application Ser. No. 11/736,519,
entitled "Apparatus and Method for Integrated Surface Treatment and
Film Deposition," all of which are filed on the same day as the
instant application. The disclosure of these related applications
is incorporated herein by reference in their entireties for all
purposes.
BACKGROUND
In the fabrication of semiconductor devices such as integrated
circuits, memory cells, and the like, a series of manufacturing
operations are performed to define features on semiconductor
wafers. The semiconductor wafers include integrated circuit devices
in the form of multi-level structures defined on a silicon
substrate. At a substrate level, transistor devices with diffusion
regions are formed. In subsequent levels, interconnect
metallization lines are patterned and electrically connected to the
transistor devices to define a desired integrated circuit device.
Also, patterned conductive layers are insulated from other
conductive layers by dielectric materials.
Reliably producing sub-micron and smaller features is one of the
key technologies for the next generation of very large scale
integration (VLSI) and ultra large scale integration (ULSI) of
semiconductor devices. However, the shrinking dimensions of
interconnect in VLSI and ULSI technologies have placed additional
demands on the processing capabilities. As circuit densities
increase, the widths of vias, contacts and other features, as well
as the dielectric materials between them, decrease to sub-micron
dimensions (e.g., less than 0.20 micrometers or less), whereas the
thickness of the dielectric layers remains substantially constant,
with the result that the aspect ratios for the features, i.e.,
their height divided by width, increase. Many traditional
deposition processes have difficulty achieving substantially
void-free and seam-free filling of sub-micron structures where the
aspect ratio exceeds 4:1.
Currently, copper and its alloys have become the metals of choice
for sub-micron interconnect technology due to its lower
resistivity. One problem with the use of copper is that copper
diffuses into silicon, silicon dioxide, and other dielectric
materials, which may compromise the integrity of devices.
Therefore, conformal barrier layers become increasingly important
to prevent copper diffusion. Copper might not adhere well to the
barrier layer; therefore, a liner layer might need to be deposited
between the barrier layer and copper. Conformal deposition of the
liner layer is also important to provide good step coverage to
assist copper adhesion and/or deposition.
Conformal deposition of the barrier layer on interconnect features
by deposition methods, such as atomic layer deposition (ALD), needs
to occur on clean surfaces to ensure good adhesion between the
barrier layer and/or liner layer, and the material(s) the barrier
layer deposited upon. Surface impurity can become a source of
defects during the heating cycles of the substrate processing.
Pre-treatment can be used to remove unwanted compounds from the
substrate surface prior to barrier deposition. In addition,
deposition by ALD might need surface pre-treatment to make the
substrate surface easier to bond with the deposition precursor to
improve the quality of barrier layer deposition.
Electro-migration (EM) is a well-known reliability problem for
metal interconnects, caused by electrons pushing and moving metal
atoms in the direction of current flow at a rate determined by the
current density. EM in copper lines is a surface phenomenon. It can
occur wherever the copper is free to move, typically at an
interface where there is poor adhesion between the copper and
another material, such as at the copper/barrier or copper/liner
interface. The quality and conformality of the barrier layer and/or
liner layer can certainly affect the EM performance of copper
interconnect. It is desirable to perform the ALD barrier and liner
layer deposition right after the surface pre-treatment, since the
pre-treated surface might be altered if the surface is exposed to
oxygen or other contaminants for a period of time.
A post-treatment after barrier and/or liner layer deposition prior
to the deposition of copper can improve the adhesion between the
barrier or liner layer with copper by removing impurities from the
substrate surface. In addition, a post-treatment after barrier or
liner layer deposition prior the deposition of a copper seed layer
by electroless method can increase nucleation sites for copper seed
layer deposition, which can improve the film quality of the copper
seed layer.
In view of the foregoing, there is a need for integrated systems
and methods that perform substrate surface treatment and film
deposition for copper interconnect with improved metal migration
performance and reduced void propagation.
SUMMARY
Broadly speaking, the embodiments fill the needs for integrated
systems and methods that perform substrate surface treatment and
film deposition for copper interconnect with improved metal
migration performance and reduced void propagation. It should be
appreciated that the present invention can be implemented in
numerous ways, including as a solution, a method, a process, an
apparatus, or a system. Several inventive embodiments of the
present invention are described below.
In one embodiment, a method of depositing films on a substrate for
copper interconnect in an integrated system is provided. The method
includes moving the substrate into a processing chamber having a
plurality of proximity heads. Selected ones of the proximity heads
is configured to perform at least one of surface treatments and
atomic layer depositions (ALDs). The processing chamber is part of
the integrated system. Within the processing chamber, barrier layer
deposition is performed over a surface of the substrate using one
of the plurality of proximity heads functioning to perform barrier
layer ALD. In addition, the method includes moving the substrate
from the processing chamber, through a transfer module of the
integrated system and into a processing module for performing
copper seed layer deposition. The processing module for performing
copper seed layer deposition is part of the integrated system.
Within the processing module for performing copper seed layer
deposition, copper seed layer deposition is performed over the
surface of the substrate. The integrated system enables
controlled-ambient transitions within the integrated system to
limit exposure of the substrate to uncontrolled ambient conditions
outside of the integrated system.
In another embodiment, an integrated system for depositing films on
a substrate for copper interconnect is provided. The integrated
system includes a processing chamber having a plurality of
proximity heads. Selected ones of the proximity heads are used for
surface treatments and atomic layer depositions (ALDs). The
integrated system also includes a vacuum transfer module coupled to
the processing chamber. The vacuum transfer module is used to
transfer the substrate in the integrated system. The integrated
system further includes a processing module for copper seed layer
deposition. In addition, the integrated system includes
controlled-ambient transfer module coupled to the processing module
for copper seed layer deposition. Additionally, the integrated
system includes a loadlock coupled to the vacuum transfer module
and to the controlled-ambient transfer module. The loadlock is used
to assist transferring the substrate between the vacuum transfer
module and to the controlled-ambient transfer module. The
integrated system enables controlled-ambient transitions within the
integrated system to limit exposure of the substrate to
uncontrolled ambient conditions outside of the integrated
system.
Other aspects and advantages of the invention will become apparent
from the following detailed description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be readily understood by the following
detailed description in conjunction with the accompanying drawings,
and like reference numerals designate like structural elements.
FIG. 1A show an exemplary cross section of an interconnect
structure prior to barrier layer deposition, in accordance of an
embodiment of the current invention.
FIG. 1B show an exemplary cross section of an interconnect
structure after deposition of barrier layer deposition and copper,
in accordance of an embodiment of the current invention.
FIG. 2 shows an exemplary ALD deposition cycle.
FIG. 3 shows a cross-sectional diagram of an ALD film grown with
limited growth sites in the beginning of ALD deposition.
FIG. 4A shows a schematic diagram of a proximity head ALD chamber,
in accordance with an embodiment of the current invention.
FIG. 4B shows a schematic diagram of a proximity head for ALD, in
accordance with an embodiment of the current invention.
FIG. 4C shows a schematic diagram of a proximity head for ALD
coupled to an RF power source over a substrate and a grounded
substrate support, in accordance with an embodiment of the current
invention.
FIG. 4D shows a schematic diagram of a thin film deposited by
proximity head ALD, in accordance with an embodiment of the current
invention.
FIG. 5A shows a schematic diagram of a chamber with a surface
treatment proximity head, in accordance with an embodiment of the
current invention.
FIG. 5B shows a schematic diagram of a proximity head for surface
treatment, in accordance with an embodiment of the current
invention.
FIG. 6A shows plurality of proximity heads for surface treatment
and deposition over a substrate, in accordance with an embodiment
of the current invention.
FIG. 6B shows plurality of proximity heads for surface treatment
and deposition over a substrate, in accordance with another
embodiment of the current invention.
FIG. 7A shows a process flow for surface treatment and film
deposition for copper interconnect, in accordance with one
embodiment of the current invention.
FIG. 7B shows an integrated system for surface treatment and film
deposition for copper interconnect, in accordance with one
embodiment of the current invention.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
Several exemplary embodiments of integrated apparatus (or systems)
and methods for substrate surface treatment and film deposition for
copper interconnect are detailed. Substrate pre-treatment prior to
barrier layer deposition can either remove surface contaminants or
can activate surface for barrier layer atomic layer deposition
(ALD). Substrate post-treatment after film deposition can either
remove surface contaminants or prepare the substrate surface for
deposition of another film, such as a copper seed layer.
Pre-treatment and post-treatment proximity heads can be integrated
with an atomic layer deposition (ALD) proximity head to complete
the film deposition and surface treatment in one chamber.
Afterwards, the substrate can be moved into a copper seed layer
deposition chamber in the same integrated system for copper seed
layer deposition. The substrate is either transferred under vacuum
or in a controlled ambient to limit the exposure to oxygen or other
contaminants. ALD barrier layer, ALD liner layer, and copper seed
layer deposited on clean or activated surfaces yield good
electro-migration (EM) performance, and avoid delamination and void
propagation.
It should be appreciated that the present invention can be
implemented in numerous ways, including a process, a method, an
apparatus, or a system. Several inventive embodiments of the
present invention are described below. It will be apparent to those
skilled in the art that the present invention may be practiced
without some or all of the specific details set forth herein.
FIG. 1A shows an exemplary cross-section of an interconnect
structure(s) after being patterned by using a dual damascene
process sequence. The interconnect structure(s) is on a substrate
50 and has a dielectric layer 100, which was previously fabricated
to form a metallization line 101 therein. The metallization line is
typically fabricated by etching a trench into the dielectric 100
and then filling the trench with a conductive material, such as
copper.
In the trench, there is a barrier layer 120, used to prevent the
copper material 122, from diffusing into the dielectric 100. The
barrier layer 120 can be made of PVD tantalum nitride (TaN), PVD
tantalum (Ta), ALD TaN, or a combination of these films. Other
barrier layer materials can also be used. Alternatively, a liner
layer can be deposited between the barrier layer 120 and the copper
material 122 to increase the adhesion between the copper material
122 and the barrier layer 120. Another barrier layer 102 is
deposited over the planarized copper material 122 to protect the
copper material 122 from premature oxidation when via holes 114 are
etched through overlying dielectric materials 104, 106 to the
barrier layer 102. The barrier layer 102 is also configured to
function as a selective etch stop and a copper diffusion barrier.
Exemplary barrier layer 102 materials include silicon nitride (SiN)
or silicon carbide (SiC).
A via dielectric layer 104 is deposited over the barrier layer 102.
The via dielectric layer 104 can be made of a material with a low
dielectric constant. Over the via dielectric layer 104 is a trench
dielectric layer 106. The trench dielectric layer 106 may be a low
K dielectric material, which can be a material same as or different
from layer 104. In one embodiment, both the via and trench
dielectric layers are made of the same material, and deposited at
the same time to form a continuous film. After the trench
dielectric layer 106 is deposited, the substrate 50 that holds the
structure(s) undergoes patterning and etching processes to form the
via holes 114 and trenches 116 by known art.
FIG. 1B shows that after the formation of via holes 114 and
trenches 116, a barrier layer 130, an optional liner layer 131, and
a copper layer 132 are deposited to line and fill the via holes 114
and the trenches 116. The barrier layer 130 can be made by
materials, such as tantalum nitride (TaN), tantalum (Ta), Ruthenium
(Ru), or a hybrid combination of these films. Barrier layer
materials may be other refractory metal compound including but not
limited to titanium (Ti), titanium nitride (TiN), tungsten (W),
zirconium (Zr), hafnium (Hf), molybdenum (Mo), niobium (Nb),
vanadium (V), and chromium (Cr), among others.
The optional liner layer 131 can be made by materials, such as
tantalum (Ta), and Ruthenium (Ru). Liner layer materials may be
other refractory metal compound including but not limited to
titanium (Ti), titanium nitride (TiN), tungsten (W), zirconium
(Zr), hafnium (Hf), molybdenum (Mo), niobium (Nb), vanadium (V),
and chromium (Cr), among others. While these are the commonly
considered materials, other barrier layer and liner layer materials
can also be used. A copper layer 132 is then deposited to fill the
via holes 114 and the trenches 116. A copper seed layer 133 can be
deposited prior to the gap-filling copper film 132 is
deposited.
As discussed above, before depositing a metallic barrier layer 130,
the substrate surface can have residual contaminants left from
etching the dielectric layers 104, 106 and the barrier layer 102 to
allow the metallic barrier layer 130 to be in contact with the
copper material 122. A cleaning process, such as Ar sputtering, can
be used to remove surface contaminant. Also as discussed above,
conformal deposition of metallic barrier layer 130 by ALD might
need surface pre-treatment to make the substrate surface easier to
bond with the deposition precursor. The reason is described
below.
Atomic layer deposition (ALD) is known to produce thin film with
good step coverage. ALD is typically accomplished by using multiple
pulses, such as two pulses, of reactants with gas purge in between,
as shown in FIG. 2. For metallic barrier deposition, a pulse of
barrier-metal-containing reactant (M) 201 is delivered to the
substrate surface, followed by a pulse of purging gas (P) 202. The
pulse of barrier-metal-containing reactant 201 delivered to the
substrate surface to form a monolayer of barrier metal, such as Ta,
on the substrate surface. In one embodiment, the pulse of purging
gas is a plasma-enhanced (or plasma-assisted) gas. The barrier
metal, such as Ta, bonds to the substrate surface, which can be
made of a dielectric material, such as low-k materials 104, 106 of
FIG. 1A, and/or a conductive material, such as copper material 122
of FIG. 1A. The purge gas 202 removes the excess
barrier-metal-containing reactant 201 from the substrate
surface.
Following the pulse of the purging gas 202, a pulse of reactant (B)
203 is delivered to the substrate surface. If the barrier material
contains nitrogen, such as TaN, the reactant (B) 203 is likely to
contain nitrogen. The reactant (B) 203 can be nitrogen-containing
gas to form TaN with the Ta on the substrate. Examples of reactant
(B) 203 include ammonia (NH.sub.3), N.sub.2, and NO. Other
N-containing precursors gases may be used including but not limited
to N.sub.xH.sub.y for x and y integers (e.g., N.sub.2H.sub.4),
N.sub.2 plasma source, NH.sub.2N(CH.sub.3).sub.2, among others. If
the barrier material contains little or no nitrogen, the reactant
(B) 203 can be a hydrogen-containing reducing gas, such as H.sub.2.
H.sub.2 is a reducing gas that reacts with the ligand bounding with
the barrier-metal in reactant M 201 to terminate the film
deposition. Following pulse 203 is a pulse of purging gas 204.
Reactants M, B, and purge gas P can be plasma enhanced or thermally
excited. In one embodiment, the pulse of reactant (B) 203 is a
plasma-enhanced (or plasma-assisted).
However, in some situations, the substrate surface does not possess
ample bonding sites for all the potential locations on the surface.
Accordingly, the barrier-metal-containing reactant M (or precursor)
bonding to the surface can result in the formation of islands and
grains which are sufficiently far apart to form poor quality ALD
film. FIG. 3 shows an ALD film with islands 301 that are grown with
limited growth sites in the beginning of ALD deposition. Between
the islands 301, there are voids 303 along the surface of the
substrate. Substrate surface, such as SiO2 or low-k material, can
be quite inert and not easy to bond with for barrier metal in the
barrier-metal-containing reactant M. Surface treatment by OH, O, or
O radical exposure can efficiently insert HOH into the SiOSi to
generate 2 Si--OH surface species that are highly reactive with the
barrier-metal-containing reactant M. The introduction of the
pre-treatment plasma into the processing chamber containing the
substrate can result in the formation of surface species at various
desired bonding sites. In order to grow continuous interfaces and
films, one embodiment of the present invention is to pre-treat the
surface of the substrate prior to ALD in order to make the surface
more susceptible to ALD, due to more deposition sites.
Due to the relatively long deposition cycle of conventional ALD
process, the deposition rate (or throughput) for some barrier or
liner layers, such as Ru, is considered too low from manufacturing
standpoint. In order to improve the deposition rate, new systems
and methods of using a proximity head for ALD of barrier layer
and/or liner layer are invented. Details of using a proximity head
to deposit an ALD film are described in commonly assigned U.S.
patent application Ser. No. 11/736,511, entitled "Apparatus and
Method for Atomic Layer Deposition," which is filed on the same day
as the instant application. This application is incorporated herein
by reference in its entirety. The ALD proximity head is briefly
introduced below.
FIG. 4A shows a schematic diagram of an ALD reactor 400 with a
proximity head 430. In reactor 400, there is a substrate 410
disposed on a substrate support 420. The proximity head 430 is
supported above substrate 410 and covers only a portion of
substrate surface. Between the proximity head 430 and the substrate
410, there is a reaction volume 450.
A gas inlet 440 and a vacuum line 465 are coupled to the proximity
head 430. The gas inlet 440 supplies reactants and purging gas to
process chamber 400. The gas inlet 440 can be coupled to a
plurality of containers that store reactants and purging gas. The
gas inlet 440 can be coupled to a container 441 that stores a first
reactant, such as reactant M described in FIG. 2. The gas inlet 440
can also be coupled to a container 443 that supplies a second
reactant, such as reactant B described in FIG. 2. As described
above, reactant B can be plasma assisted. Reactant B can be
supplied by a reactor 443' that generate plasmarized reactant B.
Alternatively, the substrate support 420 can be coupled to a radio
frequency (RF) generator to generate a plasma of reactant B when
reactant B is dispensed into the reaction volume 450, instead of
supplying plasmarized reactant B from reactor 443'. Another
alternative is to couple an RF generator 473 to the proximity head
430 to generate plasma. In one embodiment, one electrode is coupled
to the RF generator and the other electrode is grounded, during
plasma generation.
The gas inlet 440 is coupled to a container 445 that stores a
purging gas. Reactant M, purging gas and reactant B can be diluted
by a carrier gas, which can be an inert gas. During ALD deposition
cycles, one of reactants M, B and purging gas P is supplied to the
gas inlet 440. The on and off of gas supplies of these gas are
controlled by valves 451, 453, and 454. The other end of the vacuum
line 465 is a vacuum pump 460. The reaction volume 450 in FIG. 4a
is much smaller than the reaction volume in a conventional ALD
chamber. The deposition rate of proximity head ALD of barrier layer
can be 10 times or higher than the deposition rate of conventional
ALD.
FIG. 4B shows one embodiment of a proximity head 430 disposed above
substrate 410, with a reaction volume 450 between the proximity
head 430 and substrate 410. The substrate surface under the
reaction volume 450 is an active surface region 455. The proximity
head 430 has one or more gas channels 411 that supplies reactant M,
B, or purging gas P. On both sides of the gas channel 411, there
are vacuum channels 413, 415 pumping excessive reactant M, B,
purging gas, and/or reactant byproducts from the reaction volume
450. Reactant M, B, and purging gas P is passed through the gas
channel 411 sequentially, such as the sequence shown in FIG. 2. Gas
channel 411 is coupled to the gas inlet 440. When a pulse of gas,
either reactant M, B, or purging gas P, is injected from the gas
channel 411 to the substrate surface, the excess amount of gas is
pumped away from the substrate surface by the vacuum channels 413,
415, which keeps the reaction volume small and reduces the purging
or pumping time. Since the reaction volume is small, only small
amount of reactant is needed to cover the small reaction volume.
Similarly only small amount of purging gas is needed to purge the
excess reactant from the reaction volume 450. In addition, the
vacuum channels are right near the small reaction volume 450, which
assists the pumping and purging of the excess reactants, purging
gas, and reaction byproducts from the substrate surface. As a
consequence, the pulse times .DELTA.T.sub.M, .DELTA.T.sub.B,
.DELTA.T.sub.P1, and .DELTA.T.sub.P2 for reactants M, B, and
purging gas P respectively, can be greatly reduced.
As a consequence, the ALD cycle time can be reduced and the
throughput can be increased. Details of why ALD by proximity head
has higher throughput than conventional ALD are discussed commonly
assigned U.S. patent application Ser. No. 11/736,511, entitled
"Apparatus and Method for Atomic Layer Deposition," which is
mentioned above.
The proximity head for ALD can also have multiple sides with
different sides dispensing different types of processing gases.
Rotating the proximity head from side to side allows the ALD cycle
to be completed and a thin film being deposited.
FIG. 4C shows a schematic top view of an embodiment of proximity
head 430 of FIGS. 4A and 4B on top of a substrate 410. Proximity
head 430 moves across the substrate surface. In this embodiment,
the length of the proximity head L.sub.PH is equal to or greater
than the diameter of the substrate. The reaction volume under the
proximity head covers the substrate surface underneath. By moving
the proximity head across the substrate once, the entire substrate
surface is deposited with a thin film of the barrier or liner
layer. In another embodiment, the substrate 410 is moved under the
proximity head 430. In yet another embodiment, both the proximity
head 430 and the substrate 410 move, but in opposite directions to
cross each other. The thickness of the thin film deposited can be
controlled by the speed the proximity head 430 move across the
substrate 410.
FIG. 4D shows a schematic cross-sectional diagram of a thin barrier
or liner layer 420 deposited on a substrate 410, in accordance with
one embodiment of the current invention. At the edge of substrate
410, a small section 421 of thin barrier or liner layer 420 is
deposited under the proximity head. After section 421 is deposited,
the proximity is moved towards left to deposit another section 422,
which overlaps section 421 slightly. Section 423 follows section
422, and section 424 follows section 423, and so on. At the other
edge of the substrate, the deposition process stops and a complete
thin film 410 is formed.
As discussed above, in order to grow continuous interfaces and
films, one embodiment of the present invention is to pre-treat the
surface of the substrate prior to ALD in order to have the surface
more susceptible to ALD. In addition, after barrier layer and/or
liner layer is deposited on the substrate surface, the surface can
be post-treated to remove any surface contaminant or to reduce
impurities in the film, or to densify the film. Post-treatment can
also enhance nucleation of copper seed layer deposited by an
electroless process in a similar mechanism described above for
pre-treatment prior to barrier layer deposition. Copper seed layer
with enhanced nucleation has better film quality and results in
better reliability (such as EM performance) and avoids delamination
and void propagation. Surface pre-treatment and post-treatment can
be performed by proximity heads. Details of using proximity heads
for surface treatment are described in commonly assigned U.S.
patent application Ser. No. 11/736,514, entitled "Apparatus and
Method for Pre and Post Treatment of Atomic Layer Deposition,"
which is filed on the same day as the instant application. This
application is incorporated herein by reference in its entirety.
Surface treatment using proximity is briefly introduced below.
FIG. 5A shows a schematic diagram of a chamber 500 for substrate
surface treatment with a proximity head 530. In chamber 500, there
is a substrate 510 disposed on a substrate support 520. The
proximity head 530 is supported above substrate 510. Between the
proximity head 530 and the substrate 510, there is a reaction
volume 550. Since the proximity head 530 only covers a portion of
the substrate surface, the reaction volume 550 is much smaller than
conventional surface treatment that applies to the entire substrate
surface.
A gas inlet 540 and a vacuum line 565 are coupled to the proximity
head 530. The other end of the vacuum line 565 is a pump 560. The
gas inlet 540 supplies reactant gas to process chamber 500. The
excess treatment gas is pumped away from the reaction volume 550 by
the vacuum line 565. The gas inlet 540 can be coupled to a
container 541 that stores a treatment gas, such as H.sub.2. The
treatment gas can be diluted with an inert gas. As described above,
the treatment gas can be plasma assisted. In one embodiment, the
plasmarized treatment gas is supplied by a reactor 541' that
plasmarizes the treatment gas. Alternatively, the substrate support
520 can be coupled to a radio frequency (RF) generator 570 to
generate plasma to plasmarize treatment gas when treatment gas is
dispensed into the reaction volume 550, instead of supplying
plasmarized treatment from reactor 541'. Another alternative is to
couple an RF generator 573 to the proximity head 530 to generate
plasma. The inert gas can be used to sustain chamber pressure or to
sustain plasma.
FIG. 5B shows one embodiment of a proximity head 530 disposed above
substrate 510, with a reaction volume 450 between the proximity
head 530 and substrate 510. The proximity head 530 has one or more
gas channels 511 that supply treatment gas. On both sides of the
gas channel 511, there are vacuum channels 513, 515 pumping excess
treatment gas(es) from the reaction volume 550. Gas channel 511 is
coupled the container of the treatment gas. When treatment gas is
injected from the gas channel 511 to the substrate surface, the
excess amount of gas is pumped away from the substrate surface by
the vacuum channels 513, 515, which limits the reaction volume to
be substantially below the proximity head 530.
The processing gases for ALD by proximity head and the treatment
gas for surface treatment by proximity head can be plasma-enhanced
or excited by other means, such as by thermal excitation, by UV, or
by laser.
ALD proximity head(s), pre-treatment proximity head(s), and/or
post-treatment proximity head(s) can be integrated in one single
process chamber to complete the deposition and treatment processes.
In one embodiment, for a substrate to be deposited with a thin
barrier layer, such as TaN, and a liner layer, such as Ru, the
substrate can be pre-treated to clean the substrate surface or the
substrate surface can be pre-treated to prepare the surface for
barrier layer ALD deposition, as discussed above. After barrier
layer deposition and liner layer deposition, the substrate surface
can be posted-treated to prepare the surface for copper seed layer
deposition. In a single and integrated deposition/treatment
chamber, the substrate is pre-treated, deposited with a barrier
layer and a liner layer, and post-treated. FIG. 6A shows a
substrate 610 with a plurality of proximity treatment and
deposition heads over the substrate 610. Pre-treatment proximity
head 620 is used to pre-treat the substrate surface either to
remove impurities or to prepare the substrate surface for ALD.
Between the proximity head 620 and the surface of substrate 610,
there is a reaction volume 660. The substrate surface below the
reaction volume 660 is an active process region 670. Between the
proximity head 620 and the surface of substrate 610, there is a
reaction volume 660. The substrate surface below the reaction
volume 660 is an active process region 670. Next to pre-treatment
proximity head 620 is an ALD1 proximity head 630 used to deposit a
barrier layer on the substrate. After the ALD1 proximity head 630
is an ALD2 proximity head 640 used to deposit a liner layer on the
substrate. After the liner layer is deposited, the substrate is
post-treated either to remove impurities or to prepare the
substrate surface for copper seed layer deposition following. The
post-treatment is performed by a post-treatment proximity head 650.
The various proximity heads move sequentially across the substrate
surface to complete treatment and deposition surface. The treatment
and deposition processes can occur simultaneously or in
sequence.
In addition, not every proximity head in the process chamber needs
to be used for processing. For example, if pre-treatment is not
needed for some types of substrates, the pre-treatment proximity
head can move across the substrate with ALD1 proximity head, ALD2
proximity head, and post-treatment proximity head, but no treatment
gas is dispensed from the pre-treatment proximity head.
The embodiment shown in FIG. 6A is only an example of integrating
treatment proximity head with deposition proximity head. Other
combinations are possible. For example, there could be a surface
treatment after the barrier layer is deposited and before the
deposition of the liner layer. FIG. 6B shows an embodiment with a
surface treatment between two deposition steps. Inter-treatment
proximity head 635 is inserted between ALD1 proximity head 630 and
ALD2 proximity head 640.
The proximity head surface treatment chamber can be integrated with
ALD proximity heads to complete surface treatment and barrier/liner
layer(s) deposition in one process chamber. Details of integrating
proximity heads for ALD with proximity heads for surface treatment
are described in commonly assigned U.S. patent application Ser. No.
11/736,519, entitled "Apparatus and Method for Integrated Surface
Treatment and Film Deposition," which is filed on the same day as
the instant application. The application is incorporated herein by
reference in its entirety.
The gap distance between the proximity head and the substrate for
surface treatment is small and is between about 5 mm to about 10
mm. The gap distance between the proximity head and the substrate
during ALD changes from side to side and is less than about 5 mm,
such as 1 mm. The gap distance between the different proximity head
and substrate surface can be different for different proximity
heads in the chamber.
Once the substrate completes processing in the integrated surface
treatment and deposition system, such as the ones in FIGS. 6A and
6B, the substrate is ready for electroless deposition (ELD) of
copper seed layer. The substrate should not be exposed to oxygen or
other contaminants to ensure the surface is ready for depositing
high-quality electroless copper seed layer. To achieve controlled
and limited exposure to oxygen or to protect the surface from
contaminants, the substrate should be transferred or processed in
controlled environment, such as an environment under vacuum or an
environment filled with an inert gas.
FIG. 7A shows an embodiment of a process flow 700 of depositing a
barrier layer, an optional liner layer, an electroless copper seed
layer, and a copper gap-fill layer to fill an interconnect
structure. The barrier layer and the optional liner layer are
deposited in an integrated chamber that has the process capability
of surface treatment. At step 701, the substrate is moved into a
process chamber with integrated surface treatment and ALD
deposition. As described above, the integrated surface treatment
and ALD deposition chamber uses proximity heads for surface
treatment and ALD deposition, since proximity heads allow
integration of multiple processing heads in one processing
chamber.
At step 703, the substrate surface is processed in the process
chamber with integrated surface treatment and ALD deposition to
deposit a barrier layer and an optional liner layer with surface
treatment before and/or after film deposition. In one embodiment,
the substrate surface before film deposition, such as the one shown
in FIG. 1A, is pre-treated to prepare the surface for barrier layer
deposition. The surface is either cleaned to remove surface
contaminants or treated with a treatment gas to increase deposition
grown sites, as described above. In one embodiment, substrate
surface of the interconnect feature, such as surface 122a of FIG.
1A, could have been oxidized to have formed a metal oxide. The
metal oxide can be removed by an Ar sputtering process, a plasma
process using a fluorine-containing gas, such as NF.sub.3,
CF.sub.4, or a combination of both. Alternatively, the dielectric
surfaces of openings 114, 116 might need to be plasma treated to
increase deposition sites to improve film quality, as described
above. For some barrier layer, such as TaN, a liner layer, such as
Ru, might be needed before copper deposition. For other barrier
layer, such as Ru, the liner layer might not be needed. In one
embodiment, the barrier layer is TaN and the thickness of the
barrier layer is between about 20 .ANG. to about 200 .ANG.. The
liner layer is Ru and the thickness of the liner layer is between
about 20 .ANG. to about 200 .ANG..
After the barrier layer and the optional liner layer are deposited,
the substrate can be post-treated, as described above, to remove
surface contaminants or to prepare the substrate surface copper
seed layer deposition. Therefore, the integrated chamber can
include a proximity head for post-treatment. In one embodiment, the
barrier layer is hydrogen-plasma treated to produce a metal-rich
surface on the Ta, TaN, or Ru layer to provide a catalytic surface
for the subsequent copper seed deposition step.
At step 705, the substrate is moved into a copper seed layer
deposition chamber. At step 707, a copper seed layer is deposited.
In one embodiment, the thickness of the copper seed layer is
between about 25 .ANG. to about 200 .ANG.. In another embodiment,
the thickness of the copper seed layer is between about 50 .ANG. to
about 100 .ANG.. In one embodiment, the copper seed layer is
deposited by an electroless process. The thick copper bulk fill
process can be deposited by an electroless deposition (ELD) process
or by an electrochemical plating (ECP) process. At step 709, the
substrate is moved to a copper-plating chamber. However, if the
copper gap-fill layer is deposited by ELD, this step can be skipped
(optional step), since the gap-fill layer deposition will be done
in the same processing chamber as the seed layer. At step 711, a
copper gap fill layer is deposited.
Electroless copper deposition and ECP are well-known wet process.
For a wet process to be integrated in a system with controlled
processing and transporting environment, the reactor needs to be
integrated with a rinse/dryer to enable dry-in/dry-out process
capability. In addition, the system needs to be filled with inert
gas to ensure minimal exposure of the substrate to oxygen.
Recently, a dry-in/dry-out electroless copper process has been
developed. Further, all fluids used in the process are de-gassed,
i.e. dissolved oxygen is removed by commercially available
degassing systems. Details of apparatus and methods of integrating
wet and dry processes are described in commonly assigned U.S.
patent application Ser. No. 11/514,038, entitled "Processes and
Systems for Engineering a Barrier Surface for Copper Deposition"
filed on Aug. 30, 2006, which is incorporated herein by reference
in its entirety.
The electroless deposition process can be carried out in a number
of ways, such as puddle-plating, where fluid is dispensed onto a
substrate and is allowed to react in a static mode, after which the
reactants are removed and discarded, or reclaimed. In another
embodiment, the process uses a proximity process head to limit the
electroless process liquid is only in contact with the substrate
surface on a limited region. The substrate surface not under the
proximity process head is dry. Details of such process and system
can be found in U.S. application Ser. No. 10/607, 611, titled
"Apparatus And Method For Depositing And Planarizing Thin Films Of
Semiconductor Wafers," filed on Jun. 27, 2003, and U.S. application
Ser. No. 10/879,263, titled "Method and Apparatus For Plating
Semiconductor Wafers," filed on Jun. 28, 2004, both of which are
incorporated herein in their entireties.
After copper deposition at steps 707 and 711, the substrate can be
optionally moved into a substrate cleaning chamber to undergo an
optional substrate cleaning at step 713. Post-copper-deposition
clean can be accomplished by using a brush scrub clean with a
chemical solution, such as a solution containing CP72B supplied by
Air Products and Chemical, Inc. of Allentown, Pa. Other substrate
surface cleaning processes can also be used.
FIG. 7B shows an embodiment of a schematic diagram of an integrated
system 750 that allows minimal exposure of substrate surface to
oxygen or other contaminants after barrier surface preparation. In
addition, since it is an integrated system, the substrate is
transferred from one process station immediately to the next
process station, limiting the duration that the clean or treated
barrier layer or liner layer surface is exposed to oxygen. The
integrated system 750 can be used to process substrate(s) through
the process sequence of flow 700 of FIG. 7A.
As described above, the pre-treatment and post-treatment for
barrier/liner layer deposition, ALD of barrier and liner layers,
and electroless deposition of copper seed layer, copper gap-fill
layer deposition, and the optional post copper gap-fill deposition
involve a mixture of dry and wet processes. The wet processes are
typically operated near atmosphere, while the dry plasma processes
are operated at less than 1 Torr. Therefore, the integrated system
needs to be able to handle a mixture of dry and wet processes.
The integrated system 750 has 2 substrate transfer modules 755, and
757. Transfer modules 755 and 757 are equipped with robots to move
substrate 751 from one process area to another process area. The
process area could be a substrate cassette, a reactor, or a
loadlock. Substrate transfer module 755 is operated under vacuum,
at a pressure less than about 1 Torr. Substrate transfer module 755
is coupled to a process chamber 756 for integrated surface
treatment and ALD, which is also operated under vacuum, at a
pressure less than 1 Torr. In one embodiment, vacuum transfer
module 755 interfaces with a substrate loader (or substrate
cassette) 752 to bring the substrate 751 into the integrated system
or to return the substrate to the cassette 752. Between the vacuum
transfer module 755 and the cassette 752, there is a loadlock 753
to assist transferring the substrate between the atmospheric
cassette 752 and the vacuum transfer module 755, which is operated
under vacuum at a pressure compatible with processing chamber(s),
such as processing chamber 756, attached. For example, if the
substrate 751 is to be transferred from the atmospheric cassette
752 to the vacuum transfer module 755, the pressure of the loadlock
753 is first being brought to be atmospheric to allow the substrate
751 to be transferred from the atmospheric cassette 752 to the
loadlock 753. After the substrate 751 is in the loadlock 753 and
the loadlock door(s) is closed, the loadlock 753 is pumped to be in
vacuum to allow the substrate 751 to be transferred from the
loadlock 753 to the vacuum transfer module 755.
As described above in process flow 700, the substrate 751 is
brought to the integrated system 750 to deposit barrier/liner
layer(s) and copper seed layer, and a copper gap-fill layer. As
described in step 701 of process flow 700, substrate 751 is moved
to process module 756 with a chamber 756 for integrated surface
treatment and ALD barrier/liner deposition. The surface treatment
and ALD barrier/liner deposition are performed with proximity
heads, such as the ones in FIG. 6A. The surface treatment
processes, ALD barrier deposition, and ALD liner deposition
described in FIG. 6A are all dry processes and are all operated
below 1 Torr.
After substrate 751 is processed in process chamber 756 at step
702, the substrate is ready for ELD copper seed layer deposition.
Electroless copper deposition and electro-chemical plating (ECP)
are well-known wet processes. As discussed above, for a wet process
to be integrated in a system with controlled processing and
transporting environment, which has been described above, the
reactor needs to be integrated with a rinse/dryer to enable
dry-in/dry-out process capability. In addition, the system needs to
be filled with inert gas to ensure minimal exposure of the
substrate to oxygen. Recently, a dry-in/dry-out electroless copper
process has been developed. Further, all fluids used in the process
are de-gassed, i.e. dissolved oxygen is removed by commercially
available degassing systems.
Both ELD copper and ECP copper processing modules need to be
integrated with a transfer module with controlled ambient;
therefore, the substrate transport module 757 is operating under
controlled-ambient to limit the exposure of substrate to oxygen or
contaminants. In one embodiment, the substrate transport module 757
is filled with an inert gas and operated at atmospheric pressure.
Substrate 751 is moved from processing chamber 756 to ELD copper
processing module 758 for copper seed layer deposition, as
described in steps 705 and 707. Afterwards, the substrate 751 is
moved to ECP copper module 759 for copper gap-fill deposition, as
described in step 709 and 711. After ECP gap-fill, the substrate
751 could be moved into a cleaning module 761 and undergoes a
substrate cleaning, as described in step 713. However, the cleaning
after ECP copper deposition is optional. The ECP processing module
has an integrated rinse/dry, which might have sufficiently cleaned
the substrate.
While this invention has been described in terms of several
embodiments, it will be appreciated that those skilled in the art
upon reading the preceding specifications and studying the drawings
will realize various alterations, additions, permutations and
equivalents thereof. Therefore, it is intended that the present
invention includes all such alterations, additions, permutations,
and equivalents as fall within the true spirit and scope of the
invention. In the claims, elements and/or steps do not imply any
particular order of operation, unless explicitly stated in the
claims.
* * * * *